Wireless communication techniques are implemented in various ways, such as wireless local area network (w-LAN) represented by Wi-Fi, Bluetooth, and near field communication (NFC), as well as by commercialized mobile communication network access technologies. Mobile communication services, starting with 1st-generation, voice-centered mobile communication services, are evolving to high-speed, high-capacity services (e.g., high-quality video streaming services). Next-generation mobile communication services are predicted to be served through ultra-high-frequency bands of a few tens of GHz.
As communication standards such as WLAN or Bluetooth are widely used, electronic devices, e.g., mobile communication terminals, come with antenna devices that operate in various frequency bandwidths. For example, the fourth generation mobile communication service is operated in a frequency bandwidth of, e.g., 700 MHz, 1.8 GHz, or 2.1 GHz. Wi-Fi is operated in a frequency bandwidth of 2.4 GHz or 5 GHz, and Bluetooth is operated in a frequency bandwidth of 2.45 GHz, although slightly varied depending on their protocols.
The provision of stable service quality over a commercially available wireless communication network need meet a high antenna device gain and a broad beam coverage area. The next-generation mobile communication service is provided through an ultra-high-frequency bandwidth of a few tens of GHz (e.g., a frequency band within a range of about 30 GHz to about 300 GHz and with a resonant frequency wavelength of about 1 mm to 10 mm) and may thus require higher performance than the antenna device used in the legacy commercial mobile communication service presents.
Generally, as the operation frequency band increases, the straightness of radio wave may increase and loss as per transmission distance may increase. Further, as much as the increased radio wave straightness, attenuation of signal power or reflection loss by an obstacle (a building or geographic feature) may increase. Accordingly, a communication scheme with a high operation frequency may cause local shade zones in a building-dense area and significant variations in radio wave environment for partitioned spaces in the same building. Accordingly, such communication scheme with a high operation frequency bandwidth may provide an enhanced radio wave environment by turning the direction of radio waves to propagate to a shade zone.